[get rid of iorefs
Evan Martin <martine@danga.com>**20060217214003] {
hunk ./MPDMate.hs 17
-  stVolume     :: IORef Int
+  stVolume     :: Int
hunk ./MPDMate.hs 20
-processEvent :: State -> PowerMate.Event -> IO ()
-processEvent state (PowerMate.Button True)  =
+processEvent :: State -> PowerMate.Event -> IO State
+processEvent state (PowerMate.Button True) = do
hunk ./MPDMate.hs 23
-processEvent state (PowerMate.Button False) = return ()
+  return state
+processEvent state (PowerMate.Button False) = return state
hunk ./MPDMate.hs 27
+  let newvol = max 0 $ min 100 $ (stVolume state) + dir
hunk ./MPDMate.hs 30
-  vol <- readIORef (stVolume state)
-  let newvol = max 0 $ min 100 $ vol + dir
hunk ./MPDMate.hs 32
-  writeIORef (stVolume state) newvol
hunk ./MPDMate.hs 33
+  return $ state { stVolume=newvol }
hunk ./MPDMate.hs 42
+  return state
hunk ./MPDMate.hs 44
-readMPDStatus :: State -> IO ()
+readMPDStatus :: State -> IO State
hunk ./MPDMate.hs 47
-  writeIORef (stVolume state) volume
+  return $ state { stVolume=volume }
hunk ./MPDMate.hs 51
-  volume <- readIORef (stVolume state)
+  let brightness = (stVolume state)*255 `div` 100
hunk ./MPDMate.hs 53
-    PowerMate.statusInit { PowerMate.brightness=(volume*255 `div` 100) }
+    PowerMate.statusInit { PowerMate.brightness=brightness }
+
+loop :: a -> (a -> IO a) -> IO ()
+loop state func = do
+  newstate <- func state
+  loop newstate func
+  return ()  -- never reached
hunk ./MPDMate.hs 67
-  vol <- newIORef 0
-  brightness <- newIORef 0
-  let state = State { stConn=conn, stVolume=vol, stPowerMate=pm }
-  readMPDStatus state
+  state <- readMPDStatus $ State { stConn=conn, stPowerMate=pm, stVolume=0 }
hunk ./MPDMate.hs 70
-  sequence_ $ repeat $ do
+  loop state $ \state -> do
hunk ./MPDMate.hs 73
-      Nothing -> return ()
+      Nothing -> return state
}